It could be more difficult in future to bring a disability discrimination claim on mental health grounds, following an Employment Tribunal decision.
The tribunal suggested that a claimant could be required to provide evidence from a consultant psychiatrist to prove a diagnosis of stress or depression.
Previously, the threshold of proof had been lowered to make claiming easier.
The tribunal concerned a woman who said a job offer at a law firm was withdrawn after she disclosed her depression.
Having been offered the post of support lawyer at the company, the appellant, known only as J, then disclosed her history of depression to the firm's human resources department.
She says the job was then withdrawn.
J said: "It was quite a shock to me when they withdrew the job offer.
"I know that some people have negative attitudes to mental health conditions, but I didn't think in this day and age it could be expressed so boldly."
To bring a claim for disability discrimination a claimant has to prove their disability.
This is straightforward with many physical disabilities, but far more difficult with mental health, where under the Disability Discrimination Act 1995, the claimant must prove "a mental impairment which has a long term adverse affect on his ability to carry out normal day to day activities".
Until 2005, that meant proving the condition was a "clinically well-recognised" one such as bi-polar disorder, and that often required a consultant psychiatrist's report.
Following a campaign by mental health charities, that test was reduced so that claims, based on less clearly recognised and undiagnosed conditions such as depression and anxiety, could be brought with GP's notes as proof.
Tuesday's tribunal decision raises the threshold once again and makes those claims far more difficult.
J's solicitor Kiran Daurka said: "Today's decision provides little legal clarity. It has added an additional hurdle for those bringing disability discrimination claims on grounds of mental health."
Recent research from the mental health charity Mind revealed that 22% of people develop depression in the course of their careers.
It is those people who could be affected by this decision.